For example, let's say the market rate is $US500/bitcoin, what kind of discount below market rate could be expected in a trade for 10, 20, 50 or 100 bitcoin?

Depends who you're dealing with and who wants to buy or sell more. LocalBitcoins is a good place to get asking prices. You'll probably have an easier time getting closer to market if you're selling BTC, rather than buying; it really can go either way, though.

if you're looking to buy more than 100 BTC all at once, you could possibly get them from Bitpay??? (Idk what their minimum buy limit is but I have read and heard from Tony Gallippi that they do privately sell larger amounts of bitcoin to private parties who are interested)

I'm pretty sure that you will not be able to buy them with a discount because I could simply sell them in smaller increments at market rate if I wanted to get my money from them and often someone holding a substantial portion of bitcoin is worried about the risk of losing out on profit if the price rallies to a new all time high.

My opinion is that above $10K worth could be considered bulk. I would expect to give a discount if I sold 20BTC. I would also expect a better price buying that many. That's just me though. One thing about bitcoin, the price of your coins is whatever you say it is.

My opinion is that above $10K worth could be considered bulk. I would expect to give a discount if I sold 20BTC. I would also expect a better price buying that many. That's just me though. One thing about bitcoin, the price of your coins is whatever you say it is.

Welcome to my friends list I'll need to be sure to find you on mycellium local trader to buy from you the next time I want to buy 20 BTC. Hypothetically how much would you offer as a discount? half a percent? a whole percent off? Moar?

For example, let's say the market rate is $US500/bitcoin, what kind of discount below market rate could be expected in a trade for 10, 20, 50 or 100 bitcoin?

Who deals in those kinds of quantities?

There is no amount that you can buy from one seller at once to be able to command a discount below the market rate. You may be able to a trader to reduce their premium for larger orders but would not erase it completely (as they could simply sell on an exchange).

If you wanted to buy bitcoin at a discount then you should post an offer to buy at a discount verses the market price and people who specifically want to sell right away.